There are many designs of barriers to control debris when working inside a large vessel such as a pressure vessel. Various types of barriers have been used to seal off the vessel in order to prevent debris and insulation from being introduced into undesirable areas during fabrication or repair.
If a debris barrier is installed inside a completed vessel, it is normally made of many small parts in order to fit through conventional access openings. This is time-consuming, since parts must be assembled within the vessel and then disassembled for removal, and may release additional debris.
In one approach, a metal diaphragm or disk is assembled from many small parts, like a jig saw puzzle, which are held together with nuts and bolts. The parts must be small so they can be inserted and removed through access manways that are typically only 16xe2x80x3 to 24xe2x80x3 wide. These many small parts can become loose and serve as another source of debris. The metal disk is heavy, and can easily damage sensitive components nearby. Another disadvantage is that, after exposure to stress relief temperatures of up to 1220 deg F., the structure becomes very difficult to disassemble. The bolts must usually be removed with a cutting torch, thus serving as yet another potential source of debris.
In a second approach, insulation has been stuffed into a cavity as a barrier against debris. Removing the insulation is messy and difficult. Grinding dust and other debris that become trapped in the folds and cavities of the insulation are easily released back into the vessel during removal. The insulation is also friable and can serve as source of debris as it is removed.
From the preceding discussion it is apparent that a lightweight, temperature-resistant debris barrier or shield that has few or no small parts, and can be assembled in a confined space without tools after passing through a tight passage, such as a pressure vessel manway, would be welcomed by industry.
The present invention is generally drawn to a temporary, multi-function sealing debris barrier which can be configured either as a heat resistant shield or a non-heat resistant grinding shield, and more particularly to a removable debris shield to internally protect a portion of a vessel, such as a pressure vessel, during fabrication.
Accordingly, it is an object of the invention to provide a removable debris shield, suitable for use in a cylindrical vessel.
It is a further object of the invention to provide a removable debris shield, suitable for use in a closed vessel, which is lightweight.
Another object of the invention is to provide a removable debris shield, suitable for use in a closed vessel, which has few or no small parts.
Yet another object of the invention is to provide a removable debris shield, suitable for use within a confined space, which is easy to install and remove through conventional access openings and without the use of any tools.
Accordingly one aspect of the invention is drawn to a removable shield for use within a vessel, comprising: pliant material sufficient to span a desired interior portion of the vessel, a hem located around the periphery of the material and having at least one opening, and a hoop, having a first end and a second end, removably inserted through the at least one opening into the hem to extend the material across the desired interior portion of the vessel.
Another aspect of the invention is to provide a removable shield for use within a cylindrical pressure vessel having an inside diameter, comprising: pliant material having a span larger than the inside diameter of the vessel, a generally circular hem located around the periphery of the material and having at least one opening, a generally circular hoop with a diameter larger than the inside diameter of the vessel and having a first end and a second end, the hoop being removably inserted through at least one opening into the hem to extend the material across the inside diameter of the pressure vessel, and spreader bolt having a nut, and a threaded section and an unthreaded section with a shoulder therebetween, wherein the spreader bolt is removably inserted into the first and second ends of the hoop and the first and second ends of the hoop are spread apart from each other by adjusting the nut.
Yet another aspect of the invention is a method of shielding an interior portion of a vessel having an access opening from debris, comprising: providing pliant material sufficient to span a desired interior portion of the vessel, the material having a hem located around the periphery and the hem having at least one opening, providing a hoop having a first end and a second end, inserting the material and the hoop through the access opening into the vessel, and inserting the hoop through at least one opening of the hem to extend the material across the diameter of the vessel.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. For a better understanding of the present invention, and the operating advantages attained by its use, reference is made to the accompanying drawings and descriptive matter, forming a part of this disclosure, in which a preferred embodiment of the invention is illustrated.